Implants that interface with natural bone need to form a strong mechanical bond with the natural bone, both at the time of implantation and after bone growth onto or into the implant has occurred. Various geometries and manufacturing techniques for implants are known. Some implants have used rough or porous surfaces or coatings that are conducive to ingrowth or ongrowth of bone. However, it is still desirable to improve the design and manufacture of implants, and to encourage bone growth and formation of a strong mechanical bond between the implant and the bone.